A Possible Growth Mechanism for ZnO-TiO2 Composite Nanostructured Films Prepared by Electrodeposition

Abstract

ZnO-TiO2 composite nanostructured films were successfully prepared on fluorine doped tin oxide conducting glasses, from aqueous solutions, using a two-step electrochemical deposition process. The architecture of the ZnO nanorods arrays was strongly modified by the presence of TiO2 nanoparticles either on the seed layer formation or during the growth process, although the solution stirring parameter also contributed to the film arrangement. ZnO nanorods with well-defined hexagonal facets (002) were grown almost vertically over the entire substrate if no solution stirring was used during growth process. The formation of flower-like ZnO nanorods, consisting of many aggregative nanorods, requires the presence of TiO2 nanoparticles on the seed layer formation or during the growth process. In this case, the clusters of one-dimensional ZnO nanorods forming flowers were made up of numerous hexagonal straight nanorods and small clusters/agglomerates of TiO2 particles. The results showed that the diameter and length of the flower-like ZnO nanorods increased with solution stirring and, on the other hand, decreased with increase of TiO2 nanoparticles content in the bath. A possible crystal growth mechanism of ZnO and ZnO-TiO2 nanocomposites is suggested.